Red Light Therapy for Patellar Tendonitis: What the Trials Show
Red light therapy for patellar tendonitis has small but encouraging support: the closest evidence comes from tendon trials in which near-infrared laser was added to exercise, and pain fell further than with exercise alone. Jumper's knee itself has very few light trials, so light works best as an add-on to a loading programme from a physiotherapist. Below: the trials, jumper's versus runner's knee, loading stages, trial settings, where to aim, timing, ice and heat, warning signs and panel set-up.
Key takeaways
- A 2022 review of 18 lower-leg tendon and heel pain trials with 784 people, two of them on the patellar tendon, found pain 18.15 mm lower on a 100 mm scale when laser was added to exercise. Naterstad, 2022
- In a trial of 21 people with patellar tendinopathy, laser plus eccentric squats improved knee function and thigh strength more than either one alone over 4 weeks. Liu, 2014
- A 2021 review of 17 tendon trials with 835 people found pain 1.06 points lower on a 10-point scale with light plus exercise than with sham plus exercise. Tripodi, 2021
- In a 2021 trial of 76 people with jumper's knee, progressive tendon-loading exercise improved the VISA-P score by 28 points at 24 weeks, against 18 points with eccentric exercise. Breda, 2021
- A popping feeling followed by a knee you cannot straighten can mean a torn patellar tendon, which needs prompt orthopaedic assessment, not light. AAOS OrthoInfo
Does red light therapy for patellar tendonitis help?
The closest evidence says it can, when light is added to exercise: a 2022 review of lower-leg tendon and heel pain trials found pain about 18 mm lower on a 100 mm scale with laser added. Only two of its 18 trials were on the patellar tendon, so most of the support comes from neighbouring tendons.
Patellar tendonitis, also called patellar tendinopathy or jumper's knee, is an overuse injury of the tendon that joins the kneecap to the shinbone. Mayo Clinic It is most common in jumping sports such as basketball and volleyball.
| Source | What it covered | Main finding |
|---|---|---|
| Naterstad, 2022 | 18 trials, 784 people; 11 heel pain, 5 Achilles, 2 patellar tendon | Pain 14.98 mm lower than placebo straight after treatment at recommended doses; 18.15 mm lower when added to exercise |
| Tripodi, 2021 | 17 tendon trials, 835 people, near-infrared light | Pain 1.06 points lower on 10 with light plus exercise than sham plus exercise |
| Liu, 2014 | 21 people with patellar tendinopathy | Laser plus eccentric squats improved function and strength more than either alone |
| Ashok, 2018 | 8 people with jumper's knee | Laser and ultrasound, each with exercise, both improved pain and function |
When added to exercise, pain was still 19.67 mm lower at 9 weeks, and no trial reported side effects. Naterstad, 2022 Our guide to red light therapy for tendonitis covers the elbow, shoulder, Achilles and wrist trials.
What did the jumper's knee light trials find?
Very few trials have tested laser on jumper's knee, and the two small ones below both included eccentric exercise. In the larger one, with 21 people, laser plus eccentric squats beat either one alone for knee function and thigh strength over 4 weeks.
In that trial, people were split into three groups of 7: laser alone, eccentric single-leg squats alone, or both. Liu, 2014 Light went on the lower tip of the kneecap, where the tendon starts, and two points around the knee. Sessions ran six times a week for 4 weeks.
All three groups improved. The combined group improved most on function, strength and endurance, and matched the laser-only group on pain.
A second study followed 8 people aged 19 to 30, who had laser or ultrasound, each with eccentric exercise. Ashok, 2018 Both groups improved on pain and on the VISA-P, a questionnaire for jumper's knee symptoms. The authors favoured laser.
Both used clinic lasers on the skin over the knee. That is the closest evidence for red light therapy for jumper's knee, and it agrees with the wider tendon reviews.
Is jumper's knee the same as runner's knee?
No. Jumper's knee is pain in the patellar tendon just below the kneecap, while runner's knee is pain around or behind the kneecap itself.
Our guide to red light therapy for knee pain covers runner's knee, arthritis and other knee problems.
Signs that point to the patellar tendon:
- Where it hurts: tenderness just below the kneecap, with a dull ache that is worse when straightening the knee, on stairs or when squatting. Cleveland Clinic
- When it hurts: pain or stiffness after rest, and pain after running or jumping. Kingston and Richmond NHS
Can red light replace isometrics, decline squats or heavy slow resistance?
No: loading exercise is the core treatment, and light is an add-on to it. Patellar tendon programmes run for months, while light courses in trials ran for weeks.
In a 2021 trial of 76 people, progressive tendon loading beat eccentric exercise by 9 points on the VISA-P at 24 weeks. Breda, 2021 The authors recommended it as the first treatment.
A 2009 trial in 39 men compared a steroid injection, eccentric decline squats and heavy slow resistance over 12 weeks. Kongsgaard, 2009 At 6 months, gains held in both exercise groups and slipped after injections.
| Stage | Example | How often |
|---|---|---|
| 1. Isometric holds | 5 holds of 45 seconds: knee extension, Spanish squat or wall sit | Daily |
| 2. Heavy slow resistance | Leg press or squat, 3 to 4 sets, 3 seconds down and 3 seconds up | Every other day |
| 3. Faster loading | Split squats, step-downs, decline squats | Decline squats daily |
| 4. Return to sport | Jumping, landing and cutting | Built up gradually |
The stages come from a university physiotherapy clinic guideline. University of Delaware Pain up to 5 out of 10 during exercise is acceptable if it settles to baseline by the next morning.
An NHS leaflet says "there is no quick fix" and advises continuing the strengthening stage for at least 6 months. RUH Bath NHS
What settings did the patellar tendon light trials use?
Reviews and dose guides point to near-infrared laser on 2 to 3 points over the tendon, daily or every other day, for 2 to 4 weeks. The dose guide for the patellar tendon gives 8 joules in total across those points.
| Source | Light | Dose | Sessions | Weeks | With exercise? |
|---|---|---|---|---|---|
| Liu, 2014 (21 people) | Clinic laser on the lower kneecap and two points nearby | Not given in the abstract | 6 a week | 4 | One group, eccentric single-leg squats, 3 sets of 15 |
| WALT, 2010 | 780 to 860 nm laser | 8 J over 2 to 3 points on the patellar tendon | Daily, or every other day | 2, or 3 to 4 | Not specified |
| Naterstad, 2022 | 780 to 860 nm or 904 nm laser | At least 4 J per point (780 to 860 nm) or 2 J (904 nm), 2 to 3 points | Varied | Varied | Added to exercise in some trials |
| Tripodi, 2021 | Near-infrared | 0.5 to 5 J/cm² | Varied | 2 to 4 | In most trials |
The WALT figures come from its dose table, 2010.
Laser joules per point do not convert into a panel session. The pattern carries over: near-infrared light, on the tendon below the kneecap, regular sessions for several weeks, alongside exercise.
Where should you aim the light on a sore patellar tendon?
Aim at the lower tip of the kneecap and the tendon just below it, where the pain usually sits. The 21-person trial lit that spot, and dose guides cover 2 to 3 points along the tendon.
A physiotherapy guideline names the hallmark as "pain localized to inferior pole of patella". University of Delaware
- Front: centre the light just below the kneecap, over the tendon.
- Sides: turn the inner or outer side of the knee toward the light to reach both edges of the tendon.
- Skin: bare skin, with any strap, sleeve, tape or brace off for the session.
Should you use red light before or after knee rehab or training?
Tendon trials do not settle the order, so a session on the same day as your rehab, on either side of it, fits the research. If you use light before play, our guide to red light therapy for athletes suggests about 20 to 40 minutes beforehand, then your warm-up.
Isometric holds can ease tendon pain for a short time. In a crossover trial of 6 volleyball players, decline squat pain fell from 7.0 to 0.17 out of 10 after holds, and relief still held at 45 minutes. Rio, 2015 Treat holds as one stage of loading rather than a switch for pain.
Can you keep playing volleyball or basketball with jumper's knee?
Often yes, with jumping load adjusted to how the knee responds. In-season athletes reduced pain with exercise programmes without cutting their training or matches.
In a 2016 trial, 29 jumping athletes who played at least three times a week did isometric or moving exercise four times a week for 4 weeks. van Ark, 2016 Pain fell in both groups.
- Do not rest completely: reduce jumping, hopping and sprinting by pain, and stay active with swimming or cycling. RUH Bath NHS
- Next-day check: if pain is worse the next day, cut the reps, the weight or the speed.
Light is not a way to play through worsening pain.
Ice, heat or red light for a patellar tendonitis flare?
Ice suits a flare, heat may suit long-standing tendon pain, and light can sit in the same routine at a different time. Keep ice and light apart, and let the skin return to its normal temperature before a light session.
- Ice: 15 minutes at a time, several times a day, wrapped in a towel. Cleveland Clinic
- Heat: may help ongoing tendon pain by easing tight muscles and bringing blood flow. Mayo Clinic
- Strap: a jumper's knee support can be worn between sessions. NHS Borders
- Light: LED light feels mildly warm at most; warm is fine, hot is not.
When does knee pain need a doctor before any light?
A tearing or popping feeling followed by pain, a knee you cannot straighten, or a dent below the kneecap can mean a torn tendon and needs prompt orthopaedic assessment. Light does not repair a torn tendon and is not the first step for a hot, swollen or newly injured knee.
- Possible tear: the kneecap riding up or the knee buckling also point to a tear; repair works better soon after injury. AAOS OrthoInfo
- Sudden pain: sharp, severe knee pain after a sudden movement. Cleveland Clinic
- Hot or locking knee: a hot, badly swollen knee, fever, locking, giving way, or a knee that will not take weight.
- No progress: pain that persists, worsens or interferes with daily life. Mayo Clinic
- Fresh injury: no light for the first 2 to 3 days, as our guide to red light therapy for injuries explains.
Doctors usually avoid steroid injections near the patellar tendon. After any injection in the area, ask the doctor before using light there. After repair surgery, use light only once the wound has fully closed and the surgeon agrees, and never remove a brace for a session.
Ciprofloxacin raises the risk of tendinitis and tendon rupture, and can make skin sensitive to light. MedlinePlus New tendon pain on such an antibiotic goes to the prescriber. Ibuprofen or naproxen can also raise light sensitivity; our precautions rule out photosensitising medication, so check with your pharmacist or doctor first.
Our precautions also rule the panel out during pregnancy, breastfeeding or preparing for pregnancy; with epilepsy, seizures triggered by light, a thyroid condition or thyroid medication; over broken skin, including court-fall grazes; after body sunburn in the past 2 weeks; for Fitzpatrick skin types V or VI; and for anyone asleep or unconscious.
How do you use a Kivorla panel on jumper's knee?
Set the panel at knee height, put the goggles on, and sit with the bare knee slightly bent about 6 inches away, centred just below the kneecap. Run the near-infrared channels with the red lower for 10 to 15 minutes, three to five times a week, and judge it at three to four weeks.
The 9-Spectrum Red Light Therapy Panel carries 480, 590, 630, 660, 670, 810, 830, 850 and 1060 nm, each dimmable from 1 to 100%. Its 810, 830 and 850 nm channels sit inside the 780 to 860 nm band of the tendon dose guides.
- Position: hang it low on a door or wall with the included door hook, pulley, hanging cables and screws, or stand it upright on the floor, so its centre is at knee height.
- Distance: about 6 inches from the front of the knee. Starting at about 12 inches with a shorter timer in the first week is fine.
- Channels: 810, 830 and 850 nm high; 1060 nm optional; 630, 660 and 670 nm on but lower; 480 and 590 nm off; continuous light, with pulse off.
- Sides: after the front, turn each side of the knee toward the panel, one knee at a time.
- Timer: 10 to 15 minutes per area, set from 1 to 30 minutes. If no time is set, the panel stops at 5 minutes. The surface stays at or below 40°C.
- Eyes: goggles on and eyes closed for the whole session, even at knee height. Never look into the panel; see our guide to red light therapy goggles.
- Log: pain out of 10 on stairs or a single-leg decline squat, the next-morning response and your training load.
The laser trials gave small doses at a few points. To stay close to that range, use a shorter timer, turn the channels down from 100%, or step back to 12 inches.
Leave at least 6 hours between 30-minute sessions. The panel comes with goggles, a controller, a door hook and a pulley.
Standard shipping to the US, UK and Germany is free. Read the precautions before ordering. Under our return and refund policy, returns are accepted within 30 days: an unopened device with its seals intact is refunded less a 10% restocking fee, and an opened device that is undamaged and complete is refunded less 20%.
Kivorla devices are general wellness devices, not medical devices, and are not intended to treat patellar tendonitis. See a doctor for a popping feeling, a knee you cannot straighten or worsening pain, and keep your physiotherapist's loading programme.